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Finding the Fourth Proportional to 685.48, 1,028.40 and 490.72

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Solution

The fourth proportional to 685.48, 1,028.40 and 490.72 is: 736.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.48 : 1,028.40 = 490.72 : x
  2. Step 2: Convert to fraction form
    685.48/1,028.40 = 490.72/x
  3. Step 3: Cross multiply
    685.48x = 1,028.40 × 490.72
  4. Step 4: Simplify right side
    685.48x = 504,656.45
  5. Step 5: Solve for x
    x = 504,656.45/685.48
  6. Step 6: Final answer
    x = 736.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.